Thank you for the details Kaliber35.
Given the site details, I don't think solo diving vs buddy diving would have been much of a factor. Had he had any type of medical emergency I don't beleive that a buddy 200 yards off shore would have had much of a chance to save his life. Rescue breaths is about all the buddy could have done during a tow back to shore. CPR is useless until you can get the victim to a solid surface.
I'm all for solo diving but to say that a buddy couldn't have a chance to save his life in any type of medical emergency just because he was 200 yards off shore doesn't make a lot of sense. If we are talking about a massive heart attack sure but if it was a stroke or seizure or many other conditions having a buddy to get him to the surface before he drowned would be of great benefit.